The invention relates to a tube mill. Tube mills are frequently used to comminute material such as lumps of ore, for example. In tube mills, the material to be ground is placed in a tubular, rotatably arranged body and, as the body rotates, the material is pulverized either by its own gravity or by adding grinding elements such as balls, for example. The axis of rotation of the body has a horizontal orientation.
In tube mills, production throughput depends essentially on the diameter of the body. Smaller tube mills are customarily driven via gearboxes and suitable electric motors. In the case of larger tube mills, it is uneconomic to use gearbox solutions to drive the body owing to wear. Larger tube mills are therefore driven via a so-called wrap-around (ring) motor which is arranged around the body like an upright ring and drives the body directly, i.e. gearlessly, in a rotary manner. In this case there is an air gap of only a few millimeters between the rotor and stator yoke of the wrap-around motor. In order to ensure safe and reliable operation of the wrap-around motor, there must be no mechanical contact between the rotor and stator yoke of the wrap-around motor and therefore no severe vibrations of the stator yoke of the wrap-around motor during operation of the tube mill.